Fluid rotor machines (such as windmills and water wheels) are quite old in the art, and have been in use for centuries. Fluid rotor machines tend to work at their highest efficiency when the incoming fluid is flowing directly onto the movable blades or rotor, such that the direction of the fluid is perpendicular to the plane of blade movement as the blades rotate. Another way of describing this characteristic is that the direction of the fluid is parallel to the axis of rotation of the blades.
The method for directing the fluid onto the blades in the most efficient manner has varied from device to device in the past, and has lead to two basic methods of achieving this desired goal. In the first instance, a housing which surrounds the movable rotor and blades has a set of doors which are opened to allow the fluid into the rotor area. One example of this type of windmill with housing is disclosed in Cooper (U.S. Pat. No. 377,602) in which the housing has multiple doors which can be individually opened or closed to let in the fluid from the proper direction. The second common method for directing the fluid against the blades in a most efficient manner is to provide a windmill that has a relatively large tail (or vane) which automatically directs the blades into the fluid. This type of windmill is disclosed in Frisch (U.S. Pat. No. 1,963,196).
The two above methods of efficiently directing fluid against the rotor blades are combined in a patent disclosure by Bonerio (U.S. Pat. No. 1,471,095), in which the windmill system has a funnel-shaped housing that can be directed into the wind, by use of a top-mounted vane. This arrangement tends to collect a greater amount of the air in motion and condense it into a smaller cross-sectional area, thereby increasing its velocity at the points where the air passes the blades of the windmill.
Another windmill configuration is disclosed in Fisher (U.S. Pat. No. 764,571), in which a wind motor includes a main wind-wheel and an auxiliary wind-wheel. The apparatus is designed to be movable, either a automatically or otherwise, so that the wind-wheels always face squarely into the wind. In addition, an inclined deflector is provided to direct the wind onto the blades. The blades themselves have an overall scoop shape with open ends. The open end near the shaft permits the passage of wind from one blade to the next succeeding blade, which tends to the make the Fisher apparatus less efficient. Its relatively high complexity also tends to make it less reliable.
Many of the fluid rotor machines presently available require some type of movable device to insure that the blades are positioned to most efficiently collect the fluid as it arrives from various directions. The moving parts required for performing this function are a possible cause for maintenance problems and down-time. Some of the presently known fluid rotor machines also have housings which are themselves either movable, or have movable doors or openings which tend to direct fluid into the rotor and blade areas of the fluid rotor apparatus. Such movable parts, again, can be a cause for maintenance problems and down-time, and in addition cause the overall apparatus to be somewhat complex. Presently known fluid rotor devices become relatively useless if their movable parts fail to adequately perform to direct the fluid, or to move the overall rotor and blades, so that the fluid strikes the blades in an efficient manner.